In motor vehicle heating, ventilating and air conditioning systems having an air duct on a passenger compartment door that connects with an air duct on the vehicle body when the door is closed to duct air to a rear seat area, typical practice is to employ a grommet type seal mounted between the door and the vehicle body to sealingly join the ducts when the door is closed. While this has proven generally satisfactory at the hinged edge of the door, there is a tendency for the grommet to be deflected out of position at the free edge of the door because of the pronounced sliding action of the door relative to the seal at the latter edge as compared with the relatively aligned sealing action at the former or hinged edge.